Low-invasion operations involving inserting a device for diagnosis or therapy such as a catheter into a blood vessel or some other in vivo tissue are known. For example, in the treatment (diagnosis or therapy) of the coronary artery of the heart, it is necessary to insert a device such as a catheter into a blood vessel in order to perform the diagnosis or therapy treatment.
Such insertion of a catheter into a blood vessel is normally performed through a puncture formed by dissecting the femoral region. Accordingly, after the treatment is completed, it is necessary to stanch the bleeding from the puncture. However, since the blood pressure upon bleeding (bleeding blood pressure) from the femoral artery is relatively high, a person involved in the medical treatment must continue to hold down or apply pressure to the required part for a relatively long period of time using his/her finger.
In recent years, in order to perform such a stanching work more easily and reliably, a variety of devices have been developed for insertion through a wound hole to close a hole formed in a blood vessel. Examples of these devices are disclosed in U.S. Pat. No. 5,690,674 and U.S. Pat. No. 5,593,422.
U.S. Pat. No. 5,690,674 discloses a device for closing a hole formed in a blood vessel, wherein two flexible disk-like members are integrated so that they are connected at their central portions. This device is invariable of the positional relationship of the two disk-like members and is fixed by the flexibility of the two disk-like members in the wound hole.
A patient subjected to a catheter treatment and a test on the heart or the like may have blood vessel disease at a location other than the heart, and a blood vessel lesion may be present also in the femoral artery through which a catheter is inserted. For example, the blood vessel wall thickness of the femoral artery through which the catheter is inserted is about 1 mm in the case of a healthy blood vessel, but there may be cases where the blood vessel has been thickened to a wall thickness of 2 mm or more, or where the blood vessel wall has become hard through calcification. In addition, in a patient having received a catheter procedure a plurality of times, the periphery of a punctured portion of a blood vessel may have become fibrous and turned into a hard vestigium. Besides, the size of a wound formed by the insertion of a catheter differs for individual patients depending on the elasticity, wall thickness, lesion or the like of the blood vessel. Thus, there are sometimes significant differences between different patients concerning the conditions (status) of the blood vessel and the surrounding tissues of the patient in which a catheter is left to indwell.
U.S. Pat. No. 5,593,422 discloses a device in which a closing member to which a thread is attached is disposed in a blood vessel and a ring (locking member) is moved along the thread. Then ring locks the thread outside the blood vessel to close up the hole formed in the blood vessel. In the case of this device, the closing member is secured to the wall of the blood vessel by fixing the ring to the thread in some way.
Therefore, with the device disclosed in U.S. Pat. No. 5,593,422, an operation of securing the ring to the thread within subcutaneous tissues is needed. Further, after the ring is secured to the thread, it is necessary to perform an operation of cutting the thread within the subcutaneous tissues.
Furthermore, since the outside diameter of the ring needs be of a dimension allowing the ring to be inserted into the wound hole, the ring must be formed in a small size, and there is the possibility that the ring may drop into the blood vessel through the hole formed in the blood vessel.